I am having trouble reaching full boost and I am trying to troubleshoot the problem.

Non-sequential stock turbo’s.

Mods
Apexi power FC (tuned)
Blitz dual sbc spec s boost controller
HKS intake
Downpipe
Midpipe (was hi flow cat, ruled out a clogged cat)
Cat back
Underdrive pulleys


Most of the maintenance on the car is recent all have been changed in less than 6K miles ago.

Spark plugs + wires.
Fuel filter
Injectors flow tested
Etc.

Everything is good on that side of things…..what I have noticed is some of the piping/vacuum tubing could be old…so I have been going through that and fixing things associated with the system holding pressure. I had to add a vacuum nipple on one of the turbo’s…..I replaced a cracked one……and replaced another suspicious area.

I replaced the nipple on the one and boost went from 1 PSI to 5 PSI. I replaced the cracked nipple, and boost went to 7 PSI. it makes me think that the system is still not holding pressure. Where should I start looking next? Anymore vacuum lines on the intake side? Any holes that should be plugged on the throttle body area? Any significance with 7PSI boost pressure? Bad control valve somewhere?

Remember I am a newer owner of the rx7…so bare with me. I did search boost control problems…..and most is for the sequential set up….and I don’t know if much of it applies. So please help another 7 member out…as I am learning as much as I can as quickly as I can to know this car inside and out.

 

you can make a boost leak pressure tester out of PVC, something like what is sold here: http://www.boostpro.net/prodtester.html "dual pop"

 

7psi is the stock wastegate pressure. Are you sure the Boost Controller is working? Sounds like you removed the restrictor pill to the wastegate actuator and the boost controller is not working and restricting the flow the wastegate sees.

Typical leak areas are the TB o-ring, any clamps and old cracked vacuum nipples. If it is a hole in the factory IC piping you rarely see more than 2-3lbs of boost.

 

I will play around with the boost controller first....it very well might be a problem with that.

I have a FMIC....and piping.....I did check do some moving around of the piping and everything seemed pretty together.

You could be right with the boost controller.

 

I went out last night again and did some more test runs. Last night I was boosting up to .61hkPA...or roughly 8.5-8.7PSI. I played around with the boost controller and I get about the same boost at either a 30% power boost....vrs. an 80% power boost on the blitz. I was getting a steady 8-8.5PSI boost with either setting.


I think the system is leaking pressure.......I'll research more into it and find this damn leak(s). I might try going the pressurized gauge route to easily identify them.

 

Or if you can find a local tuning shop with a smoke tester that'd help you find the leak quickly.

 

Alright guys.....my buddy and I built a boost leak tester.......we pressurized the intake side of the piping (hot side intercooler piping hooked into).....the intake side looked great and there were no leaks at all (atleast that we could hear)....it held at like 15PSI.

I went cruising around yesterday and I was getting up to .69 hkpa...which is about 10PSI.....later that night I went out and it was cooler. I could only reach .45ish hkpa....or 6.6 psi. I m starting to question if the boost controller is functioning properly.....I also noticed that I would get 6.6PSI regardless of what input I put into the boost controller. (I put it into off mod, 30% gain, and 80% gain....all read the same). Could I have a kink in the vacuum line to the boost controller? Bad wastegate controller? I have never seen this car boost correctly...so I don't know what sounds normal or not? so its tough for me to troubleshoot this myself...much help is appreciated. Here are some clips of how the boost behaves.

boost controller readings.

at idle.
http://www.youtube.com/watch?v=C_MvTUeBXpk

boosting onto highway (3rd gear)...then a 4th gear pull on highway) (boost controller in "off" mode.)
http://www.youtube.com/watch?v=3e5hfdSRy38

on highway pull (boost controller set to position 1 Gain 30%).
http://www.youtube.com/watch?v=xJ7y5zWUEWs

highway pull (boost controller sret to position 2 80% gain).

http://www.youtube.com/watch?v=U4rDON1YfxE

 

You ever get this figured out ? your mods are very similar to mine. Only dif Is I have a single turbo, only hitting .52bar for some reason...

 

I did figure out my problem. my flap the opens up for the second turbo was not functioning correctly. Since I was non-seq. I remove the flap and it worked great after that and had so much more power.

I did eventually go single turbo.